Geographic information systems (GIS), sometimes referred to as spatial information systems (SIS), are specialized information systems to capture, modeling, storage, retrieval, sharing, manipulation, analysis and presentation of spatial data. The main entities are spatial objects. The spatial component may embody both geometry (location, shape etc.) and topology (spatial relationships such as adjacency). The special traits of a geometric object differs significantly from any standard type, such as integers and strings. A window query, for example, searches for all points that are contained in a given rectangle. In classical database systems, special spatial access structures are used to reduce disc access and the evaluation of spatial query predicates. However, complex data structures as well as spatial indexes can consume significant processing resources as they are constructed and additionally when queried.